Methods for producing multifunctional catalysts for upgrading pyrolysis oil

ABSTRACT

A method of making a multifunctional catalyst for upgrading pyrolysis oil includes contacting a zeolite support with a solution including at least a first metal catalyst precursor and a second metal catalyst precursor, the first metal catalyst precursor, the second metal catalyst precursor, or both, including a heteropolyacid. Contacting the zeolite support with the solution deposits or adsorbs the first metal catalyst precursor and the second catalyst precursor onto outer surfaces and pore surfaces of the zeolite support to produce a multifunctional catalyst precursor. The method further includes removing excess solution from the multifunctional catalyst precursor and calcining the multifunctional catalyst precursor to produce the multifunctional catalyst comprising at least a first metal catalyst and a second metal catalyst deposited on the outer surfaces and pore surfaces of the zeolite support.

TECHNICAL FIELD

The present specification generally relates to multifunctional catalystsand methods for producing the multifunctional catalysts for upgradingpyrolysis oil.

BACKGROUND

Crude oil can be converted to valuable chemical intermediates andproducts through one or more hydrotreating processes. The hydrotreatingprocesses can include steam cracking, in which larger hydrocarbons inthe crude oil are cracked to form smaller hydrocarbons. Steam crackingunits produce a bottom stream, which is referred to as pyrolysis oil.The pyrolysis oil may include an increased concentration of aromaticcompounds compared to the crude oil feedstock. In many crude oilprocessing facilities, this pyrolysis oil is burned as fuel. However,the aromatic compounds in the pyrolysis oil can be converted to valuablechemical intermediates and building blocks. For example, aromaticcompounds from the pyrolysis oil can be converted into xylenes, whichcan be initial building blocks for producing terephthalic acid, whichcan then be used to produce polyesters. The aromatic compounds in thepyrolysis oil can be used to produce many other valuable aromaticintermediates. The market demand for these valuable aromaticintermediates continues to grow.

SUMMARY

Accordingly, ongoing needs exist for improved multifunctional catalystsfor upgrading pyrolysis oils. Pyrolysis oils from steam crackingprocesses can be upgraded to produce valuable aromatic intermediates bycontacting the pyrolysis oil with a catalyst operable to convertmulti-ring aromatics in the pyrolysis oil to one or more C6-C8 aromaticcompounds, which can include benzene, toluene, ethylbenzene, andxylenes, other aromatic compounds, or combinations of these. Existingcatalysts operable to upgrade pyrolysis oil can include multi-metalhydrocracking catalysts that have 2 or more metals supported on catalystsupport. These multi-metal hydrocracking catalysts are typicallyprepared from conventional metal precursors, such as metallate hydrates,metal nitrates, and other conventional metal precursors.

With these multi-metal hydrocracking catalysts prepared fromconventional metal precursors, large aromatic compounds (greater than 8carbon atoms) can be converted to C6-C8 aromatic compounds at reactiontemperatures in a range of 380 degrees Celsius (° C.) to 400° C. andpressures of from 6 megapascals (MPa) to 8 MPa. Maintaining the pressurein a range of 6 MPa to 8 MPa may require a greater pressure resistanceof the facility and may consume a greater amount of energy compared tolesser pressure systems. In other words, the use of existing multi-metalhydrocracking catalyst to upgrade pyrolysis oil requires expensiveequipment rated for greater operating pressures and can consume greateramounts of energy to maintain the pressure above 6 MPa. Reducing thepressure below 6 MPa can substantially reduce the yield of C6-C8aromatics when upgrading using these existing multi-metal hydrocrackingcatalysts prepared from conventional metal catalyst precursors.

The present disclosure is directed to multifunctional catalysts forupgrading pyrolysis oil and prepared using a heteropolyacid for at leastone of the metal precursors, methods of making the multifunctionalcatalyst, and methods of upgrading pyrolysis oil using themultifunctional catalyst. The multifunctional catalyst of the presentdisclosure may produce greater yields of C6-C8 aromatic compounds fromupgrading pyrolysis oil at reduced reaction pressures compared toupgrading pyrolysis oil using existing multi-metal hydrocrackingcatalysts. The multifunctional catalyst of the present disclosure can beprepared by contacting a zeolite support with a solution containing afirst metal catalyst precursor and a second metal catalyst precursor,where at least one of the first or second metal catalyst precursor is aheteropolyacid. The heteropolyacid is a compound that includes at leastan acidic hydrogen, a transition metal, at least one heteroatom, andoxygen. It has been discovered that preparing the multifunctionalcatalyst using a heteropolyacid for at least one of the metal precursorsin place of a conventional metal precursor produces a multifunctionalcatalyst that achieves a greater yield of C6-C8 aromatic compounds atreduced reaction pressures compared to the multi-metal hydrocrackingcatalysts that are currently used to upgrade pyrolysis oil. The improvedyield and reduced operating pressure may increase the efficiency and mayreduce the capital and operating costs of the process for upgradingpyrolysis oil.

According to one or more aspects of the present disclosure, a method forproducing a multifunctional catalyst for upgrading pyrolysis oil mayinclude contacting a zeolite support with a solution comprising at leasta first metal catalyst precursor and a second metal catalyst precursor.The first metal catalyst precursor, the second metal catalyst precursor,or both, may include a heteropolyacid, and the contacting may depositthe first metal catalyst precursor and the second catalyst precursoronto outer surfaces and pore surfaces of the zeolite support to producea multifunctional catalyst precursor. The method may further includeremoving excess solution from the multifunctional catalyst precursor andcalcining the multifunctional catalyst precursor to produce themultifunctional catalyst comprising at least a first metal catalyst anda second metal catalyst deposited on the outer surfaces and poresurfaces of the zeolite support. In aspects of the present disclosure, amultifunctional catalyst for upgrading pyrolysis oil may be amultifunctional catalyst made by the methods of the present disclosure.

According to one or more other aspects of the present disclosure, amethod for upgrading pyrolysis oil may include contacting the pyrolysisoil with a multifunctional catalyst at mild reaction conditionscomprising reaction temperatures of less than 500 degrees Celsius (□)and pressures less than 6 megapascals (MPa). The pyrolysis oil mayinclude multi-ring aromatic compounds. The multifunctional catalyst maybe produced by a process comprising contacting a zeolite support with asolution comprising at least a first metal catalyst precursor and asecond metal catalyst precursor, the first metal catalyst precursor, thesecond metal catalyst precursor, or both, comprising a heteropolyacid,where the contacting causes the first metal catalyst precursor and thesecond catalyst precursor to deposit onto outer surfaces and poresurfaces of the zeolite support to produce a multifunctional catalystprecursor. The process for producing the multifunctional catalyst mayfurther include removing excess solution from the multifunctionalcatalyst precursor and calcining the multifunctional catalyst precursorto produce the multifunctional catalyst. The multifunctional catalystmay include at least a first metal catalyst and a second metal catalystsupported on the zeolite support. Contact of the pyrolysis oil with themultifunctional catalyst at the reaction conditions may convert at leasta portion of the multi-ring aromatic compounds in the pyrolysis oil toone or more C6-C8 aromatic compounds.

Additional features and advantages of the described embodiments will beset forth in the detailed description, which follows, and in part willbe readily apparent to those skilled in the art from that description orrecognized by practicing the described embodiments, including thedetailed description, which follows, the claims, as well as the appendeddrawings.

BRIEF DESCRIPTION OF THE DRAWINGS

The following detailed description of specific embodiments of thepresent disclosure can be best understood when read in conjunction withthe following drawings, in which like structure is indicated with likereference numerals and in which:

FIG. 1 schematically depicts a reactor system for upgrading pyrolysisoil, according to one or more embodiments described in this disclosure;

FIG. 2 graphically depicts an example composition for pyrolysis oilobtained from a steam cracking process for steam cracking crude oil,according to one or more embodiments described in this disclosure; and

FIG. 3 schematically depicts a reactor system for upgrading a modelpyrolysis oil in the Examples, according to one or more embodimentsdescribed in this disclosure.

For the purposes of describing the simplified schematic illustrationsand descriptions of FIGS. 1 and 3, the numerous valves, temperaturesensors, flow meters, pressure regulators, electronic controllers,pumps, and the like that may be employed and well known to those ofordinary skill in the art of certain chemical processing operations arenot included. Further, accompanying components that are often includedin typical chemical processing operations, such as valves, pipes, pumps,agitators, heat exchangers, instrumentation, internal vessel structures,or other subsystems, may not be depicted. Though not depicted, it shouldbe understood that these components are within the spirit and scope ofthe present embodiments disclosed. However, operational components, suchas those described in the present disclosure, may be added to theembodiments described in this disclosure.

Arrows in the drawings refer to process streams. However, the arrows mayequivalently refer to transfer lines, which may serve to transferprocess streams between two or more system components. Additionally,arrows that connect to system components may define inlets or outlets ineach given system component. The arrow direction corresponds generallywith the major direction of movement of the materials of the streamcontained within the physical transfer line signified by the arrow.Furthermore, arrows that do not connect two or more system componentsmay signify a product stream which exits the depicted system or a systeminlet stream which enters the depicted system. Product streams may befurther processed in accompanying chemical processing systems or may becommercialized as end products.

Additionally, arrows in the drawings may schematically depict processsteps of transporting a stream from one system component to anothersystem component. For example, an arrow from one system componentpointing to another system component may represent “passing” a systemcomponent effluent to another system component, which may include thecontents of a process stream “exiting” or being “removed” from onesystem component and “introducing” the contents of that product streamto another system component.

It should be understood that two or more process streams are “mixed” or“combined” when two or more lines intersect in the schematic flowdiagrams of FIGS. 1 and 3. Mixing or combining may also include mixingby directly introducing both streams into a like system component, suchas a separation unit, reactor, or other system component. For example,it should be understood that when two streams are depicted as beingcombined directly prior to entering a system component, the streamscould equivalently be introduced into the system component separatelyand be mixed in the system component.

Reference will now be made in greater detail to various embodiments,some embodiments of which are illustrated in the accompanying drawings.Whenever possible, the same reference numerals will be used throughoutthe drawings to refer to the same or similar parts.

DETAILED DESCRIPTION

Embodiments of the present disclosure are directed to multifunctionalcatalysts for upgrading pyrolysis oil. The multifunctional catalystsinclude a plurality of metal catalysts supported on a zeolite support.The multifunctional catalysts of the present disclosure can be preparedusing a heteropolyacid for at least one of the metal catalystprecursors. The multifunctional catalysts for upgrading pyrolysis oil ofthe present disclosure made using heteropolyacids for the metal catalystprecursors may provide greater yield of valuable aromatic compounds,such as benzene, toluene, ethylbenzene, and xylenes, from upgrading ofthe pyrolysis oil. Additionally, the multifunctional catalysts forupgrading pyrolysis oil may enable the upgrading of pyrolysis oil to beconducted at lesser reaction pressures compared to existing commerciallyavailable catalysts for upgrading pyrolysis oil.

As used in this disclosure, the term “C6-C8 aromatic compounds” mayrefer to one or more compounds having an aromatic ring, with or withoutsubstitution, and from 6 to 8 carbon atoms. The term “BTEX” may refer toany combination of benzene, toluene, ethylbenzene, para-xylene,meta-xylene, and ortho-xylene.

As used in this disclosure, the term “xylenes,” when used without adesignation of the isomer, such as the prefix para, meta, or ortho, mayrefer to one or more of meta-xylene, ortho-xylene, para-xylene, andmixtures of these xylene isomers.

As used in this disclosure, the terms “upstream” and “downstream” referto the relative positioning of unit operations with respect to thedirection of flow of the process streams. A first unit operation of asystem is considered “upstream” of a second unit operation if processstreams flowing through the system encounter the first unit operationbefore encountering the second unit operation. Likewise, a second unitoperation is considered “downstream” of the first unit operation if theprocess streams flowing through the system encounter the first unitoperation before encountering the second unit operation.

Referring now to FIG. 1, a system 10 for upgrading pyrolysis oil 12 isschematically depicted. The system 10 for upgrading pyrolysis oil 12 mayinclude a reactor unit 20 and a separation unit 30 downstream of thereactor unit 20. The reactor unit 20 may include one or a plurality ofreactors and may be operable to contact the pyrolysis oil 12 with acatalyst in reaction zone 14 to produce an upgraded effluent 22. Thecatalyst may be the multifunctional catalyst of the present disclosure.The upgraded effluent 22 may be passed to the separation unit 30, whichmay include one or a plurality of separation processes or unitoperations. The separation unit 30 may be operable to separate theupgraded effluent 22 into one or a plurality of product streams, such asa BTEX-containing stream and a greater boiling fraction 34. Although theseparation unit 30 is depicted in FIG. 1 as separating the upgradedeffluent 22 into the C6-C8 aromatic stream 32 and a greater boilingfraction 34, it is understood that the separation unit 30 may beoperable to separate the upgraded effluent 22 into a plurality ofproduct streams, one of which may include a C6-C8 aromatic stream 32.

The pyrolysis oil 12 may be a stream from a hydrocarbon processingfacility that is rich in aromatic compounds, such as multi-ring aromaticcompounds. In some embodiments, the pyrolysis oil may be a bottom streamfrom a steam cracking process. The pyrolysis oil 12 may includemono-aromatic compounds and multi-aromatic compounds. Multi-aromaticcompounds may include aromatic compounds including 2, 3, 4, 5, 6, 7, 8,or more than 8 aromatic ring structures. The pyrolysis oil 12 may alsoinclude other components, such as but not limited to saturatedhydrocarbons. Referring to FIG. 2, the composition of a typicallypyrolysis oil produced from steam cracking crude oil from Saudi Arabiais depicted. As shown in FIG. 2, the pyrolysis oil may includemono-aromatics, di-aromatics, tri-aromatics, tetra-aromatics,penta-aromatics, hexa-aromatics, and aromatic compounds having 7 or morearomatic rings (hepta and plus aromatics). The pyrolysis oil may includeelevated concentrations of di-aromatic compounds and aromatic compoundshaving greater than 7 aromatic rings, as indicated by FIG. 2. In someembodiments, the pyrolysis oil that is rich in multi-aromatic compoundsmay include greater than or equal to 50 weight percent (wt. %)multi-aromatic compounds, such as greater than or equal to 60 wt. %,greater than or equal to 65 wt. %, greater than or equal to 70 wt. %,greater than or equal to 75 wt. %, or even greater than or equal to 80wt. % multi-aromatic compounds based on the unit weight of the pyrolysisoil. The pyrolysis oil may also have a low concentration of sulfur andsulfur compounds. The pyrolysis oil may have a concentration of sulfurand sulfur-containing compounds of less than or equal to 500 parts permillion by weight (ppmw), such as less than or equal to 400 ppmw, oreven less than or equal to 300 ppmw.

The multi-aromatic compounds in the pyrolysis oil may be upgraded toC6-C8 aromatic compounds through contact with the catalyst at thereaction temperature and pressure. Converting di-aromatic andmulti-aromatic compounds to C6-C8 aromatic compounds, such as benzene,toluene, ethylbenzene, and xylenes, is a complicated reaction that mayinclude multiple synchronized and selective reactions, which may includeselective hydrogenation of one aromatic ring in a compound but not all,subsequent ring opening of the saturated naphthenic ring,hydro-dealkylation, and transalkylation.

This complex sequence of synchronized reactions for upgrading pyrolysisoil may be catalyzed using a multi-metallic catalyst having at leastcatalytic transition metals. In conventional upgrading processes, thecatalyst used to upgrade the pyrolysis oil may be a multi-metalhydrocracking catalyst. These multi-metal hydrocracking catalysts areoften synthesized using conventional metal precursors, such as metallatehydrates, metal nitrates, metal carbonates, metal hydroxides, otherconventional metal precursors, or combinations of these conventionalmetal precursors.

With these multi-metal hydrocracking catalysts made from conventionalmetal precursors, large aromatic compounds (greater than 8 carbon atoms)can be converted to C6-C8 aromatic compounds, such as but not limited tobenzene, toluene, ethylbenzene, or xylenes (BTEX), at reactiontemperatures in a range of 380° C. to 400° C. and pressures of from 6megapascals (MPa) to 8 MPa. Maintaining the pressure in a range of 6 MPato 8 MPa may require a greater pressure resistance of the facility andmay consume a greater amount of energy compared to reactions conducted alesser reaction pressures. In other words, the use of existingmulti-metal hydrocracking catalysts to upgrade pyrolysis oil may requireexpensive equipment, which is rated for greater operating pressures, andcan consume greater amounts of energy to maintain the pressure above 6MPa. Additionally, the yield of C6-C8 aromatic compounds using theseexisting multi-metal hydrocracking catalysts is low. Reducing thepressure below 6 MPa can further reduce the yield of C6-C8 aromaticcompounds when upgrading using existing multi-metal hydrocrackingcatalysts.

As previously discussed, the present disclosure is directed to amultifunctional catalyst for upgrading pyrolysis oil, themultifunctional catalyst being produced by utilizing one or moreheteropolyacids as the metal precursors for one or more of the metalcatalysts of the multifunctional catalyst. The methods of making themultifunctional catalyst for upgrading pyrolysis oil may includecontacting a zeolite support with a solution comprising at least a firstmetal catalyst precursor and a second metal catalyst precursor, thefirst metal catalyst precursor, the second metal catalyst precursor, orboth, comprising a heteropolyacid. Contacting the zeolite support withthe solution may result in deposition or adsorption of the first metalcatalyst precursor and the second catalyst precursor onto outer surfacesand pore surfaces of the zeolite support to produce a multifunctionalcatalyst precursor. The method may further include removing the excesssolution and solvent from the multifunctional catalyst precursor andcalcining the multifunctional catalyst precursor to produce themultifunctional catalyst, which includes at least a first metal catalystand a second metal catalyst deposited on the outer surfaces and poresurfaces of the zeolite support.

The multifunctional catalysts made by the methods of the presentdisclosure may increase the yield of BTEX from upgrading pyrolysis oilcompared to existing multi-metal hydrocracking catalysts. Additionally,as compared to existing multi-metal hydrocracking catalysts, themultifunctional catalysts made by the methods of the present disclosuremay also enable upgrading of the pyrolysis oil to be conducted at thesame reaction temperature and reduced reaction pressure, such as areaction pressure less than or equal to 5 MPa. The reduced reactionpressure enabled by the multifunctional catalysts of the presentdisclosure may reduce the capital and operating costs of systems forupgrading pyrolysis oils.

The method of making the multi-functional catalyst may include providinga zeolite support. The zeolite support may be a nano-zeolite having anaverage pore size of less than or equal to 2 micrometers (μm), or evenless than or equal to 1 μm. The zeolite support may have a molar ratioof silica (SiO₂) to alumina (Al₂O₃) of greater than or equal to 10, suchas greater than or equal to 20, greater than or equal to 30, greaterthan or equal to 40, greater than or equal to 50, or greater than orequal to 60. The zeolite support may have a molar ratio of SiO₂ to Al₂O₃of less than or equal to 70, such as less than or equal to 60, less thanor equal to 50, less than or equal to 40, less than or equal to 30, oreven less than or equal to 20. The zeolite support may have a molarratio of SiO₂ to Al₂O₃ of from 10 to 70. In some embodiments, thezeolite support may have a molar ratio of SiO₂ to Al₂O₃ of from 10 to60, from 10 to 50, from 10 to 40, from 20 to 70, from 20 to 60, from 20to 50, from 20 to 40, from 30 to 70, from 30 to 60, from 30 to 50, from40 to 70, from 40 to 60, from 50 to 70, or from 10 to 30. In someembodiments, the zeolite support may be a beta zeolite support. In someembodiments, the zeolite support may be a nano-beta zeolite supporthaving an average pore size of less than or equal to 2 μm.

The methods of making the multifunctional catalyst for upgradingpyrolysis oil may be a wet impregnation method in which at least one ofthe metal catalyst precursors is a heteropolyacid. The methods mayinclude contacting the zeolite support with the solution that includesat least the first metal catalyst precursor, the second metal catalystprecursor, and a solvent. The solution may also include aphosphorous-containing compound. The first metal catalyst precursor mayinclude a first metal, and the second metal catalyst precursor mayinclude a second metal different from the first metal. The first metaland the second metal may be transition metals, such as, but not limitedto transition metals in Groups 5, 6, 7, 8, 9, and 10 of theInternational Union of Pure and Applied Chemistry (IUPAC) periodic tableof elements. In some embodiments, the first metal of the first metalcatalyst precursor may be a metal selected from cobalt, molybdenum,vanadium, or combinations of these. In some embodiments, the secondmetal of the second metal catalyst precursor may be a metal selectedfrom cobalt, molybdenum, vanadium, or combinations of these, and may bedifferent from the first metal.

The first metal catalyst precursor, the second metal catalyst precursor,or both may be a heteropolyacid. The heteropolyacid may include cobalt,molybdenum, or a combination of cobalt and molybdenum; at least oneheteroatom selected from phosphorous (P), silicon (Si), arsenic (As),germanium (Ge), or combinations of these; and one or more than oneacidic hydrogen. As used in this disclosure, the term “acidic hydrogen”may refer to a hydrogen atom of the heteropolyacid that may have atendency to dissociate from the heteropolyacid in solution to form apositive ion. The heteropolyacid may also include oxygen.Heteropolyacids suitable for the first metal catalyst precursor, thesecond metal catalyst precursor, or both may have a Keggin structurehaving general formula XM₁₂O₄₀ ^(n−) or a Dawson structure having thegeneral formula XM₁₈O₈₂ ^(n−), in which X is the heteroatom selectedfrom phosphorous, silicon, arsenic, germanium, or combinations of these;M is the molybdenum and optionally one or more of cobalt, vanadium, or acombination of these; and n- is an integer indicative of the charge ofthe anion of the heteropolyacid. Examples of heteropolyacids mayinclude, but are not limited to phosphormolybdic heteropolyacid(H₃PMo₁₂O₄₀), silicomolybdic heteropolyacid (H₄SiMo₁₂O₄₀),decamolybdiccobaltate heteropolyacid (H₆[Co₂Mo₁₀O₃₈H₄]), H₄[PCoMo₁₁O₄₀],H₄[PVMo₁₁O₄₀], H₅[PV₂Mo₁₀O₄₀], H₇[PV₄Mo₆O₄₀], H₃[AsMo₁₂O₄₀],H₄[AsCoMo₁₁O₄₀], H₅[AsCo₂Mo₁₀O₄₀], H₄[AsVMo₁₁O₄₀], H₅[AsV₂Mo₁₀O₄₀],H₇[AsV₄Mo₈O₄₀], H₉[AsV₆Mo₆O₄₀], H₅[SiCoMo₁₁O₄₀], H₆[SiCo₂Mo₁₀O₄₀],₅[SiV₂Mo₁₀O₄₀], H₁₀[SiV₆Mo₆O₄₀], H₆[P₂Mo₁₈O₈₂], other heteropolyacids,salts of these heteropolyacids, or combinations of heteropolyacids.Salts of these heteropolyacids may include alkali metal salts, alkalineearth metal salts, nitrate salts, sulfate salts, or other salts of theheteropolyacid. Alkali metals may include sodium, potassium, rubidium,caesium, or combinations of these. Alkaline earth metals may include,but are not limited to magnesium, calcium, or combinations of these. Insome embodiments, the heteropolyacid may include phosphormolybdicheteropolyacid having formula H₃[PMo₁₂O₄₀]. In some embodiments, theheteropolyacid may include decamolybdodicobaltate heteropolyacid havingchemical formula H₆[Co₂Mo₁₀O₃₈H₄]. In some embodiments, theheteropolyacid may be silicomolybdic heterpolyacid having chemicalformula H₄[SiMo₁₂O₄₀]. In some embodiments, the first metal catalystprecursor, the second catalyst precursor, or both may be a metal salt ofa heteropolyacid, such as an alkali metal salt or alkaline metal salt ofthe heteropolyacid.

As previously described, the first metal catalyst precursor, the secondmetal catalyst precursor, or both may be a heteropolyacid. In someembodiments, the first metal catalyst precursor may include aheteropolyacid, and the second metal catalyst precursor may include anon-heteropolyacid precursor. In some embodiments, both the first metalcatalyst precursor and the second metal catalyst precursor may includeheteropolyacids. In some embodiments, the first metal catalyst precursormay include a first heteropolyacid, and the second metal catalystprecursor may include a second heteropolyacid that is different from thefirst heteropolyacid. For example, in some embodiments, the first metalcatalyst precursor may include a first heteropolyacid that includesmolybdenum as the metal, and the second metal catalyst precursor mayinclude a second heteropolyacid that includes cobalt as the metal. Insome embodiments, the first metal catalyst precursor and the secondmetal catalyst precursor may include the same heteropolyacid, and theheteropolyacid may include a first metal, a second metal that isdifferent from the first metal, and at least one heteroatom. Forexample, in some embodiments, the solution may includedecamolybdiccobaltate heteropolyacid having chemical formulaH₆[Co₂Mo₁₀O₃₈H₄], which include both cobalt and molybdenum and may serveas both the first metal catalyst precursor and the second metal catalystprecursor.

In some embodiments, one of the first metal catalyst precursor or thesecond metal precursor may include a non-heteropolyacid metal catalystprecursor, such as a metallate hydrate, metal nitrate, and othernon-heteropolyacid precursor. The solution may also include aphosphorous-containing compound, such as, but not limited to, phosphoricacid, phosphorous acid, or other phosphorous-containing compounds.

The first metal catalyst precursor and the second metal catalystprecursor may be dispersed or dissolved in a solvent to form thesolution. The solvent may be water. The solvent may additionally includeone or more organic solvents, such as but not limited to organicalcohols or other organic solvents. One or more than one of theheteropolyacids may be dehydrated prior to combining the heteropolyacidwith the solvent to produce the solution. The solution may have aconcentration of the first metal catalyst precursor sufficient to resultin the first metal catalyst precursor being deposited on or adsorbedonto the outer surfaces and pore surfaces of the zeolite support. Thesolution may have greater than or equal to 1 wt. %, greater than orequal to 2 wt. %, greater than or equal to 5wt. % or even greater thanor equal to 10 wt. % first metal catalyst precursor based on the totalweight of the solution before contact with the zeolite support. Thesolution may have less than or equal to 20 wt. %, less than or equal to15 wt. %, or even less than or equal to 12 wt. % first metal catalystprecursor based on the total weight of the solution before contact withthe zeolite support. In some embodiments, the solution may include from1 wt. % to 20 wt. % of the first metal catalyst precursor, such as from1 wt. % to 15 wt. %, from 1 wt. % to 10 wt. %, from 1 wt. % to 5 wt. %,from 2 wt. % to 20 wt. %, from 2 wt. % to 15 wt. %, from 2 wt. % to 10wt. %, or from 2 wt. % to 5 wt. % first metal catalyst precursor basedon the total weight of the solution before contact with the zeolitesupport.

The solution may have a concentration of the second metal catalystprecursor sufficient to result in the second metal catalyst precursorbeing deposited on or adsorbed onto the outer surfaces and pore surfacesof the zeolite support. The solution may have greater than or equal to 1wt. %, greater than or equal to 2 wt. %, greater than or equal to 5wt. %or even greater than or equal to 10 wt. % second metal catalystprecursor based on the total weight of the solution before contact withthe zeolite support. The solution may have less than or equal to 20 wt.%, less than or equal to 15 wt. %, or even less than or equal to 12 wt.% second metal catalyst precursor based on the total weight of thesolution before contact with the zeolite support. In some embodiments,the solution may include from 1 wt. % to 20 wt. % of the second metalcatalyst precursor, such as from 1 wt. % to 15 wt. %, from 1 wt. % to 10wt. %, from 1 wt. % to 5 wt. %, from 2 wt. % to 20 wt. %, from 2 wt. %to 15 wt. %, from 2 wt. % to 10 wt. %, or from 2 wt. % to 5 wt. % secondmetal catalyst precursor based on the total weight of the solutionbefore contact with the zeolite support.

The solution may be prepared and the zeolite support may be contactedwith the solution at ambient conditions. The solution may be mixed for aperiod of time prior to contacting the zeolite support with thesolution. The mixture comprising the zeolite support dispersed in thesolution may be mixed for a period of time long enough to providesufficient adsorption or deposition of the first metal catalystprecursor and the second metal catalyst precursor onto the outersurfaces and pore surfaces of the zeolite support. Contacting of thezeolite support with the solution containing the first metal catalystprecursor and the second metal catalyst precursor may result in amixture of a multifunctional catalyst precursor dispersed in thesolution. The mixture may also include the remaining first metalcatalyst precursor, second metal catalyst precursor, and any otherconstituents that are not adsorbed onto the outer surfaces and poresurfaces of the zeolite support. The multifunctional catalyst precursormay include at least the first metal catalyst precursor and the secondmetal catalyst precursor deposited on or adsorbed onto the outersurfaces or pore surfaces of the zeolite support.

As previously discussed, after contacting the zeolite support with thesolution comprising the first metal catalyst precursor and the secondmetal catalyst precursor, the excess liquids, such as solution orsolvent, may be removed from the mixture to produce a multifunctionalcatalyst precursor. Removing the liquid components may include removingthe excess solution from the multifunctional catalyst precursor anddrying the multifunctional catalyst precursor. Removing the excesssolution from the multifunctional catalyst precursor may includesubjecting the mixture to decantation, filtration, vacuum filtration, orcombinations of these. In some embodiments, removing the liquids fromthe mixture may include vacuum filtration of the mixture at atemperature of from 25° C. to 90° C. Drying the multifunctional catalystprecursor may include maintaining the multifunctional catalyst precursorat a temperature greater than or equal to the boiling temperature of thesolvent, such as at a temperature of from 90° C. to 200° C. Drying maybe conducted for a drying period sufficient to remove the solvent to alevel of less than 1 wt. % of the total weight of the multifunctionalcatalyst precursor. The drying period may be from 1 hour to 24 hours,such as from 2 hours to 12 hours. Drying may remove additional solventfrom the multifunctional catalyst through evaporation of the solvent. Insome embodiments, the solvent may be water, and drying may includemaintaining the multifunctional catalyst precursor at a temperature ofgreater than or equal to 100° C. for a drying period of greater than orequal to 1 hour.

As previously discussed, the method may further include calcining themultifunctional catalyst precursor to produce the multifunctionalcatalyst of the present disclosure. Calcining the multifunctionalcatalyst precursor may be conducted after removal of the excess solutionand solvent from the multifunctional catalyst precursor. Themultifunctional catalyst precursor may be calcined at a temperature offrom 500° C. to 600° C. and for a calcination period of from 4 hours to6 hours to produce the multifunctional catalyst.

The methods described in this disclosure are based on wet impregnationof the first and second catalyst precursors onto the outer surfaces andpore surfaces of the zeolite support. It is understood that othermethods of making the multifunctional catalyst using heteropolyacids forone or more than one of the metal catalyst precursors may also beemployed. Such methods for making the multifunctional catalyst forupgrading pyrolysis oil may include, but are not limited to,co-precipitation methods, for example.

The multifunctional catalyst for upgrading pyrolysis oil produced by themethods described in this disclosure may include at least a first metalcatalyst and a second metal catalyst supported on the outer surfaces andpore surfaces of a zeolite support. The first metal catalyst and thesecond metal catalyst may include any of the metals previous describedin this disclosure for the first metal catalyst and second metalcatalyst, respectively. The multifunctional catalyst may also includethe heteroatom from the heteropolyacid—such as but not limited tophosphorous, silicon, arsenic, or combinations of these—supported on theouter surfaces or pore surfaces of the zeolite support. In someembodiments, the first metal catalyst may be molybdenum and the secondmetal catalyst may be cobalt or vanadium, where at least the molybdenumis provided by the heteropolyacid. In some embodiments, the cobalt mayalso be provided by the same or a different heteropolyacid from theheteropolyacid that contributes the molybdenum. In some embodiments, themultifunctional catalyst may include molybdenum, cobalt, and phosphorousdeposited on the outer surfaces and pore surfaces of a nano beta zeolitesupport, where at least the molybdenum and the phosphorous are providedby the heteropolyacid. In some embodiments, the multifunctional catalystmay include molybdenum, cobalt, and silicon deposited on the outersurfaces and pore surfaces of a nano beta zeolite support.

The use of a heteropolyacid for at least one of the metal catalystprecursors may reduce the acidity and surface area of themultifunctional catalyst compared to commercially available catalyst forupgrading pyrolysis oil prepared using conventional metal catalystprecursors. The multifunctional catalyst for upgrading pyrolysis oil ofthe present disclosure made using one or more than one heteropolyacidmay have an acidity less than an acidity of an existing commerciallyavailable catalyst having the same metal catalyst species but made withconventional metal catalyst precursors. The multifunctional catalyst mayhave an acidity less than 10,000 micromoles of ammonia per gram(μmol(NH₃)/g), less than or equal to 7,000 μmol(NH₃)/g, less than orequal to 5,000 μmol(NH₃)/g, or even less than or equal to 4,000μmol(NH₃)/g. In some embodiments, the multifunctional catalyst may havean acidity of from 1,000 μmol(NH₃)/g to 5,000 μmol(NH₃)/g.

The multifunctional catalyst for upgrading pyrolysis oil producing withone or more than one heteropolyacid for at least one of the metalcatalyst precursors may have a reduced BET surface area compared toexisting commercially available catalysts for upgrading pyrolysis oilproduce with conventional metal catalyst precursors. As used herein,“BET surface area” refers to the average surface area of the metallicoxide particles as measured by the BET (Brunauer Emmett Teller) nitrogenabsorption method according to ASTM D-6556. The multifunctional catalystmay have a BET surface area less than the BET surface area of thezeolite support before preparing the multifunctional catalyst. Themultifunction catalyst may have a BET surface area of less than or equalto 400 meters squared per gram (m²/g), less than or equal to 375 m²/g,less than or equal to 350 m²/g, or even less than or equal to 325 m²/g.In some embodiments, the multifunctional catalyst may have a BET surfacearea of from 200 m²/g to 400 m²/g, such as from 200 m²/g to 375 m²/g,from 200 m²/g to 350 m²/g, or from 200 m²/g to 325 m²/g.

In some embodiments, the multifunctional catalyst for upgradingpyrolysis oil may be a multifunctional catalyst produced by a processthat may include contacting the zeolite support with the solutioncomprising at least the first metal catalyst precursor and the secondmetal catalyst precursor. The first metal catalyst precursor, the secondmetal catalyst precursor, or both, may include a heteropolyacid.Contacting the zeolite support with the solution may cause the firstmetal catalyst precursor and the second catalyst precursor to depositonto outer surfaces and pore surfaces of the zeolite support to producea multifunctional catalyst precursor. The zeolite support may includeany of the zeolite supports and may have any characteristics of thezeolite supports previously described in this disclosure. The solution,first metal catalyst precursor, second metal catalyst precursor, and oneor more heteropolyacids may have any of the compositions, properties, orcharacteristics previously described in this disclosure for these. Themethod may further include removing the excess solution from themultifunctional catalyst precursor, and calcining the multifunctionalcatalyst precursor to produce the multifunctional catalyst. Each of thecontacting step, removing excess solution step, and calcining step maybe conducted under any of the process conditions previously described inthis disclosure in relation to each of these process steps. Themultifunctional catalyst produced by this method may include at least afirst metal catalyst and a second metal catalyst deposited on the outersurfaces and the pore surfaces of the zeolite support. Themultifunctional catalyst may have any of the compositions or propertiespreviously described in this disclosure for the multifunctionalcatalyst.

The multifunctional catalyst prepared by the methods described in thisdisclosure may be used to upgrade pyrolysis oil to produce one or morevaluable aromatic intermediates, such as but not limited to benzene,toluene, ethylbenzene, xylenes, other aromatic compounds, orcombinations of these. In some embodiments, a method for upgradingpyrolysis oil may include contacting the pyrolysis oil with themultifunctional catalyst at mild reaction conditions comprising reactiontemperatures of less than 500° C. and pressures less than 6 MPa. Thepyrolysis oil may have any of the compositions or characteristicspreviously described in this disclosure for pyrolysis oil. In someembodiments, the pyrolysis oil may include multi-ring aromaticcompounds. The multifunctional catalyst may be made by of the methods orprocesses for making the multifunctional catalyst described in thisdisclosure and may have any properties, compositions, or attributesdescribed in this disclosure for the multifunctional catalyst. In someembodiments, the multifunctional catalyst may be produced by a processthat includes contacting the zeolite support with the solutioncomprising at least the first metal catalyst precursor and the secondmetal catalyst precursor, the first metal catalyst precursor, the secondmetal catalyst precursor, or both, including a heteropolyacid. Thecontacting may cause the first metal catalyst precursor and the secondcatalyst precursor to deposit or be adsorbed onto the outer surfaces andpore surfaces of the zeolite support to produce a multifunctionalcatalyst precursor. The process for producing the multifunctionalcatalyst may include removing excess solution from the multifunctionalcatalyst precursor, and calcining the multifunctional catalyst precursorto produce the multifunctional catalyst. The multifunctional catalystmay include a first metal catalyst and a second metal catalyst supportedon the zeolite support.

Contact of the pyrolysis oil with the multifunctional catalyst at thereaction conditions may convert at least a portion of the multi-ringaromatic compounds in the pyrolysis oil to one or more C6-C8 aromaticcompounds. The at least a portion of the multi-ring aromatic compoundsconverted to one or more C6-C8 compounds may include at least 30%, atleast 40%, at least 50%, at least 60%, at least 70%, or at least 80% ofthe multi-ring aromatic compounds in the pyrolysis oil. The C6-C8aromatic compounds may include, but are not limited to, one or more ofbenzene, toluene, ethylbenzene, xylene, or combinations of these. Insome embodiments, contacting the pyrolysis oil with the multifunctionalcatalyst at the reactions conditions may convert the portion of themulti-ring aromatic compounds in the pyrolysis oil to C6-C8 aromaticcompounds in a single step, without conducting a subsequent chemicalreaction step.

Contacting of the pyrolysis oil with the multifunctional catalyst mayconducted at a reaction temperature in a range comparable to thereaction temperatures for processes for upgrading pyrolysis oil usingcommercially-available catalysts prepared using conventional metalcatalyst precursors. In some embodiments, the pyrolysis oil may becontacted with the multifunctional catalyst at a reaction temperature ofless than or equal to 500° C., less than or equal to 450° C., or evenless than or equal to 400° C. The pyrolysis oil may be contacted withthe multifunctional catalyst at a reaction temperature of greater thanor equal to 350° C., greater than or equal to 380° C., or even greaterthan or equal to 400° C. In some embodiments, pyrolysis oil may becontacted with the multifunctional catalyst at a reaction temperature offrom 350° C. to 500° C., from 350° C. to 450° C., from 350° C. to 400°C., from 380° C. to 500° C., from 380° C. to 450° C., from 380° C. to400° C., from 400° C. to 500° C., or from 400° C. to 425° C.

Contacting of the pyrolysis oil with the multifunctional catalyst may beconducted at a reaction pressure less than the reactions pressuresnecessary for upgrading pyrolysis oil using the commercially-availablecatalysts prepared using conventional metal catalyst precursors. In someembodiments, the pyrolysis oil may be contacted with the multifunctionalcatalyst at a reaction pressure less than 6 MPa, less than or equal to 5MPa, or even less than or equal to 4 MPa. In some embodiments, thepyrolysis oil may be contacted with the multifunctional catalyst at areaction pressure greater than or equal to 0.1 MPa, greater than orequal to 1 MPa, or even greater than or equal to 2 MPa. In someembodiments, the pyrolysis oil may be contacted with the multifunctionalcatalyst at a reaction pressure of from 0.1 MPa to 5 MPa, from 0.1 MPato 4 MPa, from 1 MPa to 5 MPa, from 1 MPa to 4 MPa, from 2 MPa to 5 MPa,or even from 2 MPa to 4 MPa.

In some embodiments, the method of upgrading pyrolysis oil may furtherinclude separating an upgraded pyrolysis oil from the multifunctionalcatalyst. Separating the upgraded pyrolysis oil from the multifunctionalcatalyst may be conducted using any known method or process ofseparating a fluid from a particulate solid.

Upgrading pyrolysis oil by contacting with the multifunctional catalystof the present disclosure prepared using heteropolyacids may produce agreater yield of C6-C8 aromatic compounds, such as one or more than oneof benzene, toluene, ethylbenzene, xylenes, or combinations of these,compared to upgrading the pyrolysis oil by contacting withcommercially-available catalysts prepared using conventional metalcatalyst precursors. In some embodiments, upgrading pyrolysis oil bycontacting the pyrolysis oil with the multifunctional catalyst of thepresent disclosure prepared using heteropolyacids may produce a combinedyield of C6-C8 aromatic compounds of greater than or equal to 30 wt. %,greater than or equal to 32 wt. %, or even greater than or equal to 35wt. %, based on the total weight of the upgraded pyrolysis oil separatedfrom the multifunctional catalyst.

EXAMPLES

The following examples illustrate the methods of the present disclosurefor producing multifunctional catalysts for upgrading pyrolysis oil andthe methods for upgrading pyrolysis oil using the multifunctionalcatalysts. The Examples are not intended to limit the scope of thepresent disclosure in any way, in particular with respect to specificmass flow rates, stream compositions, temperatures, pressures, time onstream, amounts of catalytic metals on the zeolite support, or othervariables fixed for the purposes of conducting the experiments.

Comparative Example 1 NaNO-Beta Zeolite Support

For Comparative Example 1, beta zeolite support particles with no metalcompounds deposited on the outer surfaces or pore surfaces were providedas a baseline comparison. It is noted that beta zeolite by itselfprovides at least some activity for catalyzing cracking of hydrocarbons.The beta zeolite support of Comparative Example 1 was CP814E nano-betazeolite obtained from Zeolyst International. The nano-beta zeolitesupport particles had a ratio of the molar amount of silica (SiO₂)divided by the molar amount of alumina (Al₂O₃) of 25.

Comparative Example 2 Comparative Catalyst for Upgrading Pyrolysis Oil

For Comparative Example 2, a comparative catalyst comprising a firstcatalyst metal and second catalyst metal deposited on the outer surfacesand pore surfaces of a nano-beta zeolite support was prepared usingconventional metal precursors and no heteropolyacids. The first metalcatalyst precursor was ammonium molybdate tetrahydrate having chemicalformula [(NH₃)₆Mo₇O₂₄.4H₂O], which was obtained from Sigma-Aldrich. Thesecond metal catalyst precursor was cobalt (II) nitrate hexahydratehaving chemical formula [Co(NO₃)₂.6H₂O], which was also obtained fromSigma-Aldrich. The nano-beta zeolite catalyst support was the nano-betazeolite catalyst support of Comparative Example 1.

The comparative catalyst of Comparative Example 2 was produced by adding10 grams of the nano-beta zeolite catalyst support from ComparativeExample 1 to a round bottom flask. A Solution A was prepared bydissolving 3.08 grams of [(NH₃)₆Mo₇O₂₄.4H₂O] in 50 milliliters (mL) ofdistilled water. A Solution B was then prepared by dissolving 2.65 gramsof the second metal catalyst precursor [Co(NO₃)₂.6H₂O] in 50 mL ofdistilled water. The amounts of [(NH₃)₆Mo₇O₂₄.4H₂O] and [Co(NO₃)₂.6H₂O]were selected to provide a final metal loading in the comparativecatalyst of Comparative Example 2 of 3 wt. % Co and 12 wt. % Mo,respectively. Solution A and Solution B were then mixed together andadded to nano-beta zeolite catalyst support in the round bottom flask.The combined solution and the nano-beta zeolite catalyst support weremixed for 2 hours. The water was removed from the nano-beta zeolitecatalyst support impregnated with the first and second metal catalystprecursors under vacuum at a temperature of 50° C., and the solid samplewas dried overnight at a temperature of 100° C. The solid sample wasthen calcined at a temperature of 500° C. for five hours to obtain thecomparative catalyst of Comparative Example 2.

Comparative Example 3 Comparative Phosphorous-Containing Catalyst forUpgrading Pyrolysis Oil

For Comparative Example 3, a comparative phosphorous-containing catalystcomprising a first catalyst metal, second catalyst metal, andphosphorous deposited on the outer surfaces and pore surfaces of anano-beta zeolite support was prepared using conventional metalprecursors and no heteropolyacids. The first metal catalyst precursorwas ammonium molybdate tetrahydrate having chemical formula[(NH₃)₆Mo₇O₂₄.4H₂O], which was obtained from Sigma-Aldrich. The secondmetal catalyst precursor was cobalt (II) nitrate hexahydrate havingchemical formula [Co(NO₃)₂.6H₂O], which was also obtained fromSigma-Aldrich. The nano-beta zeolite catalyst support was the nano-betazeolite catalyst support of Comparative Example 1. Phosphoric acid(H₃PO₄) obtained from Sigma-Aldrich was used to incorporate thephosphorous.

The comparative phosphorous-containing catalyst of Comparative Example 3was produced by adding 10 grams of the nano-beta zeolite catalystsupport from Comparative Example 1 to a round bottom flask. A Solution Awas prepared by dissolving 3.08 grams of the first metal catalystprecursor [(NH₃)₆Mo₇O₂₄.4H₂O] in 50 milliliters (mL) of distilled water.A Solution B was then prepared by dissolving 2.65 grams of the secondmetal catalyst precursor [Co(NO₃)₂.6H₂O] in 50 mL of distilled water.The amounts of [(NH₃)₆Mo₇O₂₄.4H₂O] and [Co(NO₃)₂.6H₂O] were selected toprovide a final metal loading in the comparative catalyst of ComparativeExample 3 of 3 wt. % Co and 12 wt. % Mo, respectively. Solution A andSolution B were then mixed together, and 0.15 grams of phosphoric acidwas dissolved in the combined solution to produce Solution C. Solution Cwas then added to the nano-beta zeolite catalyst support in the roundbottom flask and mixed for 2 hours. The water was removed from thenano-beta zeolite catalyst support impregnated with the first and secondmetal catalyst precursors under vacuum at a temperature of 50° C., andthe solid sample was dried overnight at a temperature of 100° C. Thesolid sample was then calcined at a temperature of 500° C. for fivehours to obtain the comparative phosphorous-containing catalyst ofComparative Example 3.

Example 4 Multifunctional Catalyst for Upgrading Pyrolysis Oil PreparedUsing a Heteropolyacid.

In Example 4, a multifunctional catalyst according to the presentdisclosure and comprising a first metal catalyst, a second metalcatalyst, and phosphorous deposited on the outer surfaces and poresurfaces of a nano-beta zeolite support was prepared using aheteropolyacid for first metal catalyst precursor. The first metalcatalyst precursor was phosphormolybdic heteropolyacid having chemicalformula [H₃PMo₁₂O₄₀], which was obtained from Sigma-Aldrich. The secondmetal catalyst precursor was cobalt (II) nitrate hexahydrate havingchemical formula [Co(NO₃)₂.6H₂O], which was also obtained fromSigma-Aldrich. The nano-beta zeolite catalyst support was the nano-betazeolite catalyst support of Comparative Example 1.

The multifunctional catalyst of Example 4 was produced by adding 10grams of the nano-beta zeolite catalyst support from Comparative Example1 to a round bottom flask. Solution A was prepared by dissolving 2.89grams of the heteropolyacid of the first metal catalyst precursor[H₃PMo₁₂O₄₀] in 50 milliliters (mL) of distilled water. Solution B wasthen prepared by dissolving 2.24 grams of the second metal catalystprecursor [Co(NO₃)₂.6H₂O] in 50 mL of distilled water. The amounts ofthe first metal catalyst precursor and second metal catalyst precursorwere calculated to provide the same metal loading as the comparativecatalysts of Comparative Examples 2 and 3 (3 wt. % Co and 12 wt. % Mo)Solution A and Solution B were then mixed together and added to thenano-beta zeolite catalyst support in the round bottom flask. Thecombined solution and nano-beta zeolite catalyst support were mixed for2 hours. The water was removed from the nano-beta zeolite catalystsupport impregnated with the first and second metal catalyst precursorsunder vacuum at a temperature of 50° C., and the solid sample was driedovernight at a temperature of 100° C. The solid sample was then calcinedat a temperature of 500° C. for five hours to obtain the multifunctionalcatalyst of Example 4.

Example 5 Upgrading Pyrolysis Oil

In Example 5, the comparative catalysts of Comparative Examples 1, 2,and 3 and the multifunctional catalyst of Example 4 were used to upgradea model pyrolysis oil composition to produce at least benzene, toluene,ethylbenzene, and xylene. 1-methylnaphthalene obtained fromSigma-Aldrich was used as the model pyrolysis oil.

Referring to FIG. 3, the apparatus 100 in which the model pyrolysis oilupgrading was conducted is schematically depicted. The apparatus 100included a fixed bed reactor 110 with the catalyst loaded in zone 111.The fixed bed reactor 110 was maintained in a hot box 112 to maintainthe fixed bed reactor 110 at constant temperature. The liquid feed 116,which included the model pyrolysis oil (1-methylnaphthalene) wasintroduced to the fixed bed reactor 110 using a liquid pump 120.Hydrogen 118 and nitrogen 119 can also be added to the liquid feed 116upstream of the fixed bed reactor 110. The liquid feed 116 was passedthrough a heat exchanger 130 to adjust a temperature of the liquid feed116 before passing it to the fixed bed reactor 110. The liquid feed 116was contacted with the catalyst in the fixed bed reactor 110, thecontacting causing reaction of at least the model pyrolysis oil(1-methylnaphthalene) to upgrade the model pyrolysis oil to produce aliquid product stream 114 comprising at least benzene, toluene,ethylbenzene, and xylene. The operating conditions of the fixed bedreactor 110 are listed in Table 1.

The liquid product stream 114 was passed from the fixed bed reactor 110to a liquid gas separator 140, in which the liquid product stream 114was separated into a gaseous fraction 142 comprising the lesser boilingtemperature constituents and a liquid fraction 144 comprising thegreater boiling point fractions and unreacted model pyrolysis oil(1-methylnaphthalene). The liquid fraction 144 was analyzed forcomposition. The gaseous fraction 142 was passed to an online gaschromatograph for analysis of the composition of the gaseous fraction142. The compositions of the gaseous fraction 142 and liquid fraction144 were then used to determine the yield for each of the constituentsof the liquid product stream 114. The yields for each of the compoundsproduced in the fixed bed reactor for each of the catalysts ofComparative Examples 1-3 and Example 4 are provided subsequently inTable 1. The yields for each of the constituents in Table 1 are providedin weight percent based on the total mass flow rate of the liquidproduct stream 114.

TABLE 1 Results of Upgrading of Model Pyrolysis Oil with Catalysts ofComparative Examples 1-3 and Example 4 Comparative ComparativeComparative Example 1 Example 2 Example 3 Example 4 Catalyst SupportNano-beta Nano-beta Nano-beta Nano-beta zeolite zeolite zeolite zeoliteFirst Metal Catalyst Precursor N/A (NH₃)₆Mo₇O₂₄•4H₂O (NH₃)₆Mo₇O₂₄•4H₂OH₃PMo₁₂O₄₀ Second Metal Catalyst Precursor N/A Co(NO₃)₂•6H₂OCo(NO₃)₂•6H₂O Co(NO₃)₂•6H₂O Phosphorous Precursor N/A N/A H₃PO₄H₃PMo₁₂O₄₀ Catalyst Acidity (μmol(NH₃)/g) 10788.0 4703.6 14570.0 3258.8Catalyst BET Surface Area (m²/g) 502.485 329.104 320.730 350.632Reaction Temperature (° C.) 400 400 400 400 Weight Hourly Space Velocity(hour⁻¹) 1.2 1.2 1.2 1.2 Total Pressure (MPa) 3 3 3 3 Total Conversionof 1-methylnaphthalene (%) 32.3 86.1 81.8 86.7 Time on Stream (hour) 2020 20 20 Benzene Yield (wt. %) 0.14 4.60 4.36 6.25 Toluene Yield (wt. %)0.58 12.96 11.75 17.64 Ethylbenzene Yield (wt. %) 0.06 2.47 2.22 3.71Total Xylene Yield (wt. %) 0.14 7.30 5.68 9.27 Para-Xylene Yield (wt. %)0.03 1.78 1.40 2.28 Meta-Xylene Yield (wt. %) 0.07 3.83 2.99 4.86Ortho-Xylene Yield (wt. %) 0.04 1.69 1.29 2.13 C(3-4)-Benzene* Yield(wt. %) 1.68 15.02 9.09 14.44 Tetralin Yield (wt. %) 0.04 0.60 0.23 0.34Naphthalene Yield (wt. %) 0.98 2.53 2.31 2.92 Methyltetralin Yield (wt.%) 24.25 12.91 23.61 19.71 Other 2-Ar (wt. %) 6.18 8.89 7.32 7.36 TotalBTEX Yield** (wt. %) 0.90 27.3 24.0 36.7 *C(3-4)-Benzene refers tobenzene substituted with one or more alkyl group for which the totalnumber of carbon atoms in the alkyl group is 3 or 4. **Total BTEX Yieldrefers to the total combined yield of benzene, toluene, ethylbenzene,and xylenes (para-xylene, meta-xylene, and ortho-xylene).

As shown in Table 1, the multifunctional catalyst of Example 4 providedthe best performance for upgrading the model pyrolysis oil(1-methylnaphthalene) to benzene, toluene, ethylbenzene, and xylenes(BTEX). The total BTEX yield obtained using the multifunctional catalystof Example 4 was 36.7 wt. %, which is an improvement of greater than 34%over the comparative catalyst of Comparative Example 2. Themultifunctional catalyst of Example 4 also resulted in the greatestoverall conversion of 1-methylnaphthalene. Thus, at the same temperatureand pressure, the multifunctional catalyst of the present applicationprovides greater yield of BTEX compounds at lower pressures compared toconventional catalysts used to upgrade pyrolysis oils. Even though themultifunctional catalyst of Example 4 contained phosphorous, themultifunctional catalyst of Example 4 still exhibited a catalyst acidityless than the comparative catalyst of Comparative Example 2, which didnot include phosphorous. Thus, the reduced acidity provided by thestructure of the heteropolyacid used as the first metal catalystprecursor in the multifunctional catalyst of Example 4 may increase theyield of BTEX, compared to the comparative catalysts of ComparativeExamples 2 and 3.

In a first aspect of the present disclosure, a method of making amultifunctional catalyst for upgrading pyrolysis oil may comprisecontacting a zeolite support with a solution comprising at least a firstmetal catalyst precursor and a second metal catalyst precursor. Thefirst metal catalyst precursor, the second metal catalyst precursor, orboth, may comprise a heteropolyacid. The contacting may deposit thefirst metal catalyst precursor and the second catalyst precursor ontoouter surfaces and pore surfaces of the zeolite support to produce amultifunctional catalyst precursor. The method may further includeremoving excess solution from the multifunctional catalyst precursor andcalcining the multifunctional catalyst precursor to produce themultifunctional catalyst comprising at least a first metal catalyst anda second metal catalyst deposited on the outer surfaces and poresurfaces of the zeolite support.

In a second aspect of the present disclosure, a multifunctional catalystfor upgrading pyrolysis oil may comprise a multifunctional catalystproduced by a process comprising contacting a zeolite support with asolution comprising at least a first metal catalyst precursor and asecond metal catalyst precursor, the first metal catalyst precursor, thesecond metal catalyst precursor, or both, comprising a heteropolyacid.The contacting may cause the first metal catalyst precursor and thesecond catalyst precursor to deposit onto outer surfaces and poresurfaces of the zeolite support to produce a multifunctional catalystprecursor. The process may further include removing excess solution fromthe multifunctional catalyst precursor and calcining the multifunctionalcatalyst precursor to produce the multifunctional catalyst. Themultifunctional catalyst made by the process may include at least afirst metal catalyst and a second metal catalyst deposited on the outersurfaces and the pore surfaces of the zeolite support.

A third aspect of the present disclosure may include either of the firstor second aspects, in which the heteropolyacid comprises at least onemetal selected from cobalt, molybdenum, vanadium, or combinations ofthese and at least one heteroatom selected from phosphorous, silicon,arsenic, or combinations of these.

A fourth aspect of the present disclosure may include any of the firstthrough third aspects, in which the first metal catalyst precursorcomprises a heteropolyacid.

A fifth aspect of the present disclosure may include any of the firstthrough fourth aspects, in which the first metal catalyst precursorcomprises a first heteropolyacid and the second metal catalyst precursorcomprises a second heteropolyacid that is different from the firstheteropolyacid.

A sixth aspect of the present disclosure may include any of the firstthrough fifth aspects, in which the heteropolyacid comprisesphosphormolybdic heteropolyacid having formula H₃PMo₁₂O₄₀.

A seventh aspect of the present disclosure may include any of the firstthrough fifth aspects, in which the first metal catalyst precursor andthe second metal catalyst precursor are the same heteropolyacid, and theheteropolyacid comprises a first metal, a second metal that is differentfrom the first metal, and at least one heteroatom.

An eighth aspect of the present disclosure may include the seventhaspect, in which the heteropolyacid comprises decamolybdodicobaltateheteropolyacid.

A ninth aspect of the present disclosure may include any of the firstthrough eighth aspects, further comprising dehydrating theheteropolyacid prior to contacting the zeolite support with thesolution.

A tenth aspect of the present disclosure may include any of the firstthrough ninth aspects, in which the multifunctional catalyst precursoris calcined at a temperature of 500-600 □ and for a time of from 4 hourto 6 hours to produce the multifunctional catalyst.

An eleventh aspect of the present disclosure may include any of thefirst through tenth aspects, in which the zeolite support comprises anano beta zeolite having an average pore size of less than or equal to 2micrometers.

A twelfth aspect of the present disclosure may include any of the firstthrough eleventh aspects, in which the zeolite support comprises a molarratio of silica to alumina of from 10 to 70.

A thirteenth aspect of the present disclosure may be the multifunctionalcatalyst produced according to any of the first through twelfth aspects.

A fourteenth aspect of the present disclosure may include any of thefirst through thirteenth aspects, in which the first metal catalystcomprises molybdenum and the second metal catalyst comprises cobalt.

A fifteenth aspect of the present disclosure may include any of thefirst through fourteenth aspects, further comprising phosphorousdeposited on the outer surfaces and pore surfaces of the zeolitesupport.

A sixteenth aspect of the present disclosure may include any of thefirst through fifteenth aspects, in which the multifunctional catalysthas an acidity of less than 10,000 micromoles of ammonia per gram(μmol(NH₃)/g).

A seventeenth aspect of the present disclosure may include any of thefirst through sixteenth aspects, in which the multifunctional catalysthas an acidity of from 1000 μmol(NH₃)/g to 5000 μmol(NH₃)/g.

An eighteenth aspect of the present disclosure may include any of thefirst through seventeenth aspects, in which the multifunction catalysthas a BET surface area of less than or equal to 400 meters squared pergram (m²/g).

A nineteenth aspect of the present disclosure may include any of thefirst through eighteenth aspects, in which the multifunction catalysthas a BET surface area of from 200 m²/g to 400 m²/g.

In a twentieth aspect of the present disclosure, a multifunctionalcatalyst for upgrading pyrolysis oil comprises one or more cobaltcompounds, one or more molybdenum compounds, and phosphorous supportedon a zeolite support, where at least one of the molybdenum compounds,cobalt compounds, or phosphorous is provided by a heteropolyacidprecursor.

A twenty-first aspect of the present disclosure may include thetwentieth aspect, in which the multifunctional catalyst has an acidityof less than 10,000 micromoles of ammonia per gram (μmol(NH₃)/g).

A twenty-second aspect of the present disclosure may include either ofthe twentieth or twenty-first aspects, in which the multifunctionalcatalyst has an acidity of from 1000 μmol(NH₃)/g to 5000 μmol(NH₃)/g.

A twenty-third aspect of the present disclosure may include any of thetwentieth through twenty-second aspects, in which the multifunctioncatalyst has a BET surface area of less than or equal to 400 meterssquared per gram (m²/g).

A twenty-fourth aspect of the present disclosure may include any of thetwentieth through twenty-third aspects, in which the multifunctioncatalyst has a BET surface area of from 200 m²/g to 400 m²/g.

A twenty-fifth aspect of the present disclosure may include any of thetwentieth through twenty-fourth aspects, in which the heteropolyacidcomprises phosphormolybdic heteropolyacid having formula H₃PMo₁₂O₄₀.

A twenty-sixth aspect of the present disclosure may include any of thetwentieth through twenty-fifth aspects, in which the heteropolyacidcomprises decamolybdodicobaltate heteropolyacid.

A twenty-seventh aspect of the present disclosure may include any of thetwentieth through twenty-sixth aspects, in which the zeolite supportcomprises a nano beta zeolite having an average pore size of less thanor equal to 2 micrometers.

A twenty-eighth aspect of the present disclosure may include any of thetwentieth through twenty-seventh aspects, in which the zeolite supportcomprises a molar ratio of silica to alumina of from 10 to 70.

In a twenty-ninth aspect of the present disclosure, a method forupgrading pyrolysis oil includes contacting the pyrolysis oil with amultifunctional catalyst at mild reaction conditions comprising reactiontemperatures of less than 500 degrees Celsius (□) and pressures lessthan 6 megapascals (MPa). The pyrolysis oil may include multi-ringaromatic compounds. The multifunctional catalyst may be produced by aprocess comprising contacting a zeolite support with a solutioncomprising at least a first metal catalyst precursor and a second metalcatalyst precursor, the first metal catalyst precursor, the second metalcatalyst precursor, or both, comprising a heteropolyacid. The contactingmay cause the first metal catalyst precursor and the second catalystprecursor to deposit onto outer surfaces and pore surfaces of thezeolite support to produce a multifunctional catalyst precursor. Theprocess for producing the multifunctional catalyst may further includeremoving excess solution from the multifunctional catalyst precursor andcalcining the multifunctional catalyst precursor to produce themultifunctional catalyst. The multifunctional catalyst comprises atleast a first metal catalyst and a second metal catalyst supported onthe zeolite support. Contact of the pyrolysis oil with themultifunctional catalyst at the reaction conditions converts at least aportion of the multi-ring aromatic compounds in the pyrolysis oil to oneor more C6-C8 aromatic compounds.

A thirtieth aspect of the present disclosure may include thetwenty-ninth aspect, in which the C6-C8 aromatic compounds include oneor more of benzene, toluene, ethylbenzene, xylene, or combinations ofthese.

A thirty-first aspect of the present disclosure may include thetwenty-ninth or thirtieth aspects, in which contacting the pyrolysis oilwith the multifunctional catalyst at the reaction conditions convertsthe portion of the multi-ring aromatic compounds in the pyrolysis oil toC6-C8 aromatic compounds in a single step, without conducting asubsequent chemical reaction step.

A thirty-third aspect of the present disclosure may include any of thetwenty-ninth through thirty-first aspects, where contacting thepyrolysis oil with the multifunctional catalyst results a yield of C6-C8aromatic compounds of at least 30%.

A thirty-fourth aspect of the present disclosure may include any of thetwenty-ninth through thirty-third aspects, further comprising separatingan upgraded pyrolysis oil from the multifunctional catalyst.

A thirty-fifth aspect of the present disclosure may include any of thetwenty-ninth through thirty-fourth aspects, in which the pyrolysis oilis contacted with the multifunctional catalyst at a temperature of from300 □ to 450 □.

A thirty-sixth aspect of the present disclosure may include any of thetwenty-ninth through thirty-fifth aspects, in which the pyrolysis oil iscontacted with the multifunctional catalyst at a pressure of from 0.1MPa to 5 MPa.

A thirty-seventh aspect of the present disclosure may include any of thetwenty-ninth through thirty-sixth aspects, in which the heteropolyacidcomprises at least one metal selected from cobalt, molybdenum, vanadium,or combinations of these and at least one heteroatom selected fromphosphorous, silicon, arsenic, or combinations of these.

A thirty-eighth aspect of the present disclosure may include any of thetwenty-ninth through thirty-seventh aspects, in which the first metalcatalyst precursor comprises a heteropolyacid.

A thirty-ninth aspect of the present disclosure may include any of thetwenty-ninth through thirty-eighth aspects, in which the first metalcatalyst precursor comprises a first heteropolyacid and the second metalcatalyst precursor comprises a second heteropolyacid that is differentfrom the first heteropolyacid.

A fortieth aspect of the present disclosure may include any of thetwenty-ninth through thirty-ninth aspects, in which the heteropolyacidcomprises phosphormolybdic heteropolyacid having formula H₃PMo₁₂O₄₀.

A forty-first aspect of the present disclosure may include any of thetwenty-ninth through thirty-ninth aspects, in which the first metalcatalyst precursor and the second metal catalyst precursor are the sameheteropolyacid, and the heteropolyacid comprises a first metal, a secondmetal that is different from the first metal, and at least oneheteroatom.

A forty-second aspect of the present disclosure may include theforty-first aspect, in which the heteropolyacid comprisesdecamolybdodicobaltate heteropolyacid.

A forty-third aspect of the present disclosure may include any of thetwenty-ninth through forty-second aspects, further comprisingdehydrating the heteropolyacid prior to contacting the zeolite supportwith the solution.

A forty-fourth aspect of the present disclosure may include any of thefirst through forty-third aspects, in which the multifunctional catalystprecursor is calcined at a temperature of 500-600 □ and for a time offrom 4 hour to 6 hours to produce the multifunctional catalyst.

A forty-fifth aspect of the present disclosure may include any of thetwenty-ninth through forty-fourth aspects, in which the zeolite supportcomprises a nano beta zeolite having an average pore size of less thanor equal to 2 micrometers.

A forty-sixth aspect of the present disclosure may include any of thetwenty-ninth through forty-fifth aspects, in which the zeolite supportcomprises a molar ratio of silica to alumina of from 10 to 70.

A forty-seventh aspect of the present disclosure may include any of thetwenty-ninth through forty-sixth aspects, in which the first metalcatalyst comprises molybdenum and the second metal catalyst comprisescobalt.

A forty-eighth aspect of the present disclosure may include any of thetwenty-ninth through forty-seventh aspects, further comprisingphosphorous deposited on the outer surfaces and pore surfaces of thezeolite support.

A forty-ninth aspect of the present disclosure may include any of thetwenty-first through forty-eighth aspects, in which the multifunctionalcatalyst has an acidity of less than 10,000 micromoles of ammonia pergram (μmol(NH₃)/g).

A fiftieth aspect of the present disclosure may include any of thetwenty-ninth through forty-ninth aspects, in which the multifunctionalcatalyst has an acidity of from 1000 μmol(NH₃)/g to 5000 μmol(NH₃)/g.

A fifty-first aspect of the present disclosure may include any of thetwenty-ninth through fiftieth aspects, in which the multifunctioncatalyst has a BET surface area of less than or equal to 400 meterssquared per gram (m²/g).

A fifty-second aspect of the present disclosure may include any of thetwenty-ninth through fifty-first aspects, in which the multifunctioncatalyst has a BET surface area of from 200 m²/g to 400 m²/g.

It should now be understood that various aspects of the multifunctionalcatalyst for upgrading pyrolysis oil, methods of making themultifunctional catalyst for upgrading pyrolysis oil usingheteropolyacids as the metal catalyst precursors, and methods ofupgrading pyrolysis oils using the methods are described and suchaspects may be utilized in conjunction with various other aspects.

Throughout this disclosure, ranges are provided for various propertiesand characteristics of the multifunctional catalyst and variousprocessing parameters and operating conditions for the methods formaking the multifunctional catalyst and upgrading pyrolysis oil. It willbe appreciated that when one or more explicit ranges are provided theindividual values and the sub-ranges formed within the range are alsointended to be provided as providing an explicit listing of all possiblecombinations is prohibitive. For example, a provided range of 1-10 alsoincludes the individual values, such as 1, 2, 3, 4.2, and 6.8, as wellas all the ranges, which may be formed within the provided bounds, suchas 1-8, 2-4, 6-9, and 1.3-5.6.

It should be apparent to those skilled in the art that variousmodifications and variations can be made to the described embodimentswithout departing from the spirit and scope of the claimed subjectmatter. Thus, it is intended that the specification cover themodifications and variations of the various described embodimentsprovided such modification and variations come within the scope of theappended claims and their equivalents.

1. A method of making a multifunctional catalyst for upgrading pyrolysisoil, the method comprising: contacting a zeolite support with a solutioncomprising at least a first metal catalyst precursor and a second metalcatalyst precursor, where the first metal catalyst precursor, the secondmetal catalyst precursor, or both, comprises a heteropolyacid having atleast one heteroatom selected from the group consisting of phosphorous,silicon, germanium, arsenic, and combinations of these, where thezeolite support comprises a molar ratio of silica to alumina of from 10to 70, and where the contacting deposits the first metal catalystprecursor and the second metal catalyst precursor onto outer surfacesand pore surfaces of the zeolite support to produce a multifunctionalcatalyst precursor; removing excess solution from the multifunctionalcatalyst precursor; and calcining the multifunctional catalyst precursorat a temperature of at least 500 degrees Celsius to produce themultifunctional catalyst comprising at least a first metal catalyst anda second metal catalyst deposited on the outer surfaces and poresurfaces of the zeolite support.
 2. The method of claim 1, in which theheteropolyacid comprises at least one metal selected from cobalt,molybdenum, vanadium, or combinations of these.
 3. The method of claim1, in which the first metal catalyst precursor comprises a firstheteropolyacid and the second metal catalyst precursor comprises asecond heteropolyacid that is different from the first heteropolyacid.4. The method of claim 1, in which the heteropolyacid comprisesphosphormolybdic heteropolyacid having formula H₃PMo₁₂O₄₀.
 5. (canceled)6. The method of claim 1, in which the heteropolyacid comprisesdecamolybdodicobaltate heteropolyacid.
 7. The method of claim 1, furthercomprising dehydrating the heteropolyacid prior to contacting thezeolite support with the solution.
 8. The method of claim 1, in whichthe multifunctional catalyst precursor is calcined at a temperature offrom 500 degrees Celsius to 600 degrees Celsius and for a time of from 4hour to 6 hours to produce the multifunctional catalyst.
 9. The methodof claim 1, in which the zeolite support comprises a nano beta zeolitehaving an average pore size of less than or equal to 2 micrometers.10-20. (canceled)
 21. The method of claim 1, where the contacting causesthe first metal catalyst precursor and the second metal catalystprecursor to be adsorbed directly onto the outer surfaces and poresurfaces of the zeolite support to produce the multifunctional catalystprecursor.
 22. The method of claim 1, where the heteropolyacid has aKeggin structure having general formula XM₁₂O₄₀ ^(n−) or a Dawsonstructure having the general formula XM₈O₈₂ ^(n−), in which X is theheteroatom; M is molybdenum and optionally one or more of cobalt,vanadium, or a combination of these; and n- is an integer indicative ofthe charge of the anion of the heteropolyacid.
 23. The method of claim1, where the solution consists essentially of the first metal precursor,the second metal precursor, a solvent, and, optionally, aphosphorous-containing compound.
 24. The method of claim 1, where thephosphorous-containing compound comprises phosphoric acid or phosphorousacid.